Question

My SQL data of column Price is of type float.
When I use DataReader to read in a row and try to access the column value as

reader["Price"]

I got a compiler error: “The best overloaded method match for decimal.Parse(string) has some invalid arguments.”

I want assign this value to a decimal variable, how do I do so?
I got the compiler error above when I tried:

decimal price;
price = decimal.Parse(reader["Price"]);

Answer 1

The return type for reader["Price"] is object. To do what you’re trying to do use this:

price = decimal.Parse(reader["Price"].ToString()); 

However, if there’s the slightest change you can end up with a string that cannot be converted to a Decimal consider using the Decimal.TryParse Method which will allow you to determine if the conversion was successful.

EDIT
The SqlDataReader has a number of different GetXXX methods that allow you to retrieve typed data from a column in a DataReader without first having to cast to/from an intermediate type. I originally advised you to use SqlDataReader.GetDecimal because I saw the type you wanted to retrieve is a decimal. I see now that the SQL data type of the this data is actually float so I was going to advise that you use SqlDataReader.GetFloat. I tested this though and got an invalid cast exception. The reason for this is that the SQL float is not compatible with the .NET float data type.

So I checked table in SQL Server Data Types and Their .NET Framework Equivalents on MSDN and found that the SQL float is the equivalent to the .NET double. I tried SqlDataReader.GetDouble and was able to retrieve data without error. Since you want a decimal though, you’ll need to cast:

price = (decimal)reader.GetDouble(reader.GetOrdinal("Price"));